1
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Apostolopoulos A, Kawamoto N, Chow SYA, Tsuiji H, Ikeuchi Y, Shichino Y, Iwasaki S. dCas13-mediated translational repression for accurate gene silencing in mammalian cells. Nat Commun 2024; 15:2205. [PMID: 38467613 PMCID: PMC10928199 DOI: 10.1038/s41467-024-46412-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 02/27/2024] [Indexed: 03/13/2024] Open
Abstract
Current gene silencing tools based on RNA interference (RNAi) or, more recently, clustered regularly interspaced short palindromic repeats (CRISPR)‒Cas13 systems have critical drawbacks, such as off-target effects (RNAi) or collateral mRNA cleavage (CRISPR‒Cas13). Thus, a more specific method of gene knockdown is needed. Here, we develop CRISPRδ, an approach for translational silencing, harnessing catalytically inactive Cas13 proteins (dCas13). Owing to its tight association with mRNA, dCas13 serves as a physical roadblock for scanning ribosomes during translation initiation and does not affect mRNA stability. Guide RNAs covering the start codon lead to the highest efficacy regardless of the translation initiation mechanism: cap-dependent, internal ribosome entry site (IRES)-dependent, or repeat-associated non-AUG (RAN) translation. Strikingly, genome-wide ribosome profiling reveals the ultrahigh gene silencing specificity of CRISPRδ. Moreover, the fusion of a translational repressor to dCas13 further improves the performance. Our method provides a framework for translational repression-based gene silencing in eukaryotes.
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Grants
- JP20H05784 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP21H05278 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP21H05734 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP23H04268 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20H05786 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP23H02415 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP20K07016 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP23K05648 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP21K15023 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP23KJ2175 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP20gm1410001 Japan Agency for Medical Research and Development (AMED)
- JP20gm1410001 Japan Agency for Medical Research and Development (AMED)
- JP23gm6910005h0001 Japan Agency for Medical Research and Development (AMED)
- JP23gm6910005 Japan Agency for Medical Research and Development (AMED)
- JP20gm1410001 Japan Agency for Medical Research and Development (AMED)
- Pioneering Projects MEXT | RIKEN
- Pioneering Projects MEXT | RIKEN
- Exploratory Research Center on Life and Living Systems (ExCELLS), 23EX601
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Affiliation(s)
- Antonios Apostolopoulos
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561, Japan
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan
| | - Naohiro Kawamoto
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan
| | - Siu Yu A Chow
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
| | - Hitomi Tsuiji
- Education and Research Division of Pharmacy, School of Pharmacy, Aichi Gakuin University, Nagoya, Aichi, 464-8650, Japan
| | - Yoshiho Ikeuchi
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Institute for AI and Beyond, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yuichi Shichino
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan.
| | - Shintaro Iwasaki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561, Japan.
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan.
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2
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Athilingam T, Nelanuthala AVS, Breen C, Karedla N, Fritzsche M, Wohland T, Saunders TE. Long-range formation of the Bicoid gradient requires multiple dynamic modes that spatially vary across the embryo. Development 2024; 151:dev202128. [PMID: 38345326 PMCID: PMC10911119 DOI: 10.1242/dev.202128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 01/03/2024] [Indexed: 02/15/2024]
Abstract
Morphogen gradients provide essential positional information to gene networks through their spatially heterogeneous distribution, yet how they form is still hotly contested, with multiple models proposed for different systems. Here, we focus on the transcription factor Bicoid (Bcd), a morphogen that forms an exponential gradient across the anterior-posterior (AP) axis of the early Drosophila embryo. Using fluorescence correlation spectroscopy we find there are spatial differences in Bcd diffusivity along the AP axis, with Bcd diffusing more rapidly in the posterior. We establish that such spatially varying differences in Bcd dynamics are sufficient to explain how Bcd can have a steep exponential gradient in the anterior half of the embryo and yet still have an observable fraction of Bcd near the posterior pole. In the nucleus, we demonstrate that Bcd dynamics are impacted by binding to DNA. Addition of the Bcd homeodomain to eGFP::NLS qualitatively replicates the Bcd concentration profile, suggesting this domain regulates Bcd dynamics. Our results reveal how a long-range gradient can form while retaining a steep profile through much of its range.
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Affiliation(s)
- Thamarailingam Athilingam
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
- Mechanobiology Institute, National University of Singapore, Singapore117411
| | - Ashwin V. S. Nelanuthala
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore117558
| | | | - Narain Karedla
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, OX3 7LF, UK
| | - Marco Fritzsche
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, OX3 7LF, UK
| | - Thorsten Wohland
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore117558
- Department of Chemistry, National University of Singapore, Singapore117558
| | - Timothy E. Saunders
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
- Mechanobiology Institute, National University of Singapore, Singapore117411
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore117558
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3
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Palumbo RJ, Yang Y, Feigon J, Hanes SD. Catalytic activity of the Bin3/MePCE methyltransferase domain is dispensable for 7SK snRNP function in Drosophila melanogaster. Genetics 2024; 226:iyad203. [PMID: 37982586 PMCID: PMC10763541 DOI: 10.1093/genetics/iyad203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/27/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023] Open
Abstract
Methylphosphate Capping Enzyme (MePCE) monomethylates the gamma phosphate at the 5' end of the 7SK noncoding RNA, a modification thought to protect 7SK from degradation. 7SK serves as a scaffold for assembly of a snRNP complex that inhibits transcription by sequestering the positive elongation factor P-TEFb. While much is known about the biochemical activity of MePCE in vitro, little is known about its functions in vivo, or what roles-if any-there are for regions outside the conserved methyltransferase domain. Here, we investigated the role of Bin3, the Drosophila ortholog of MePCE, and its conserved functional domains in Drosophila development. We found that bin3 mutant females had strongly reduced rates of egg-laying, which was rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 promotes fecundity by repressing P-TEFb. bin3 mutants also exhibited neuromuscular defects, analogous to a patient with MePCE haploinsufficiency. These defects were also rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 and MePCE have conserved roles in promoting neuromuscular function by repressing P-TEFb. Unexpectedly, we found that a Bin3 catalytic mutant (Bin3Y795A) could still bind and stabilize 7SK and rescue all bin3 mutant phenotypes, indicating that Bin3 catalytic activity is dispensable for 7SK stability and snRNP function in vivo. Finally, we identified a metazoan-specific motif (MSM) outside of the methyltransferase domain and generated mutant flies lacking this motif (Bin3ΔMSM). Bin3ΔMSM mutant flies exhibited some-but not all-bin3 mutant phenotypes, suggesting that the MSM is required for a 7SK-independent, tissue-specific function of Bin3.
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Affiliation(s)
- Ryan J Palumbo
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Yuan Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Steven D Hanes
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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4
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Baron N, Purushotham R, Pullaiahgari D, Bose P, Zarivach R, Shapira M. LeishIF4E2 is a cap-binding protein that plays a role in Leishmania cell cycle progression. FASEB J 2024; 38:e23367. [PMID: 38095329 DOI: 10.1096/fj.202301665r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/14/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023]
Abstract
Leishmania encode six paralogs of the cap-binding protein eIF4E and five eIF4G candidates, forming unique complexes. Two cap-binding proteins, LeishIF4E1 and LeishIF4E2, do not bind any identified LeishIF4Gs, thus their roles are intriguing. Here, we combine structural prediction, proteomic analysis, and interaction assays to shed light on LeishIF4E2 function. A nonconserved C-terminal extension was identified through structure prediction and sequence alignment. m7 GTP-binding assays involving both recombinant and transgenic LeishIF4E2 with and without the C-terminal extension revealed that this extension functions as a regulatory gate, modulating the cap-binding activity of LeishIF4E2. The interactomes of the two LeishIF4E2 versions were investigated, highlighting the role of the C-terminal extension in binding to SLBP2. SLBP2 is known to interact with a stem-loop structure in the 3' UTRs of histone mRNAs. Consistent with the predicted inhibitory effect of SLBP2 on histone expression in Xenopus laevis, a hemizygous deletion mutant of LeishIF4E2, exhibited an upregulation of several histones. We therefore propose that LeishIF4E2 is involved in histone expression, possibly through its interaction between SLBP2 and LeishIF4E2, thus affecting cell cycle progression. In addition, cell synchronization showed that LeishIF4E2 expression decreased during the S-phase, when histones are known to be synthesized. Previous studies in T. brucei also highlighted an association between TbEIF4E2 and SLBP2, and further reported on an interaction between TbIF4E2 and S-phase-abundant mRNAs. Our results show that overexpression of LeishIF4E2 correlates with upregulation of cell cycle and chromosome maintenance proteins. Along with its effect on histone expression, we propose that LeishIF4E2 is involved in cell cycle progression.
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Affiliation(s)
- Nofar Baron
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Rajaram Purushotham
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | | | - Priyanka Bose
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Raz Zarivach
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Michal Shapira
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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5
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Hernández G, Vazquez-Pianzola P. eIF4E as a molecular wildcard in metazoans RNA metabolism. Biol Rev Camb Philos Soc 2023; 98:2284-2306. [PMID: 37553111 DOI: 10.1111/brv.13005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 07/01/2023] [Accepted: 07/25/2023] [Indexed: 08/10/2023]
Abstract
The evolutionary origin of eukaryotes spurred the transition from prokaryotic-like translation to a more sophisticated, eukaryotic translation. During this process, successive gene duplication of a single, primordial eIF4E gene encoding the mRNA cap-binding protein eukaryotic translation initiation factor 4E (eIF4E) gave rise to a plethora of paralog genes across eukaryotes that underwent further functional diversification in RNA metabolism. The ability to take different roles is due to eIF4E promiscuity in binding many partner proteins, rendering eIF4E a highly versatile and multifunctional player that functions as a molecular wildcard. Thus, in metazoans, eIF4E paralogs are involved in various processes, including messenger RNA (mRNA) processing, export, translation, storage, and decay. Moreover, some paralogs display differential expression in tissues and developmental stages and show variable biochemical properties. In this review, we discuss recent advances shedding light on the functional diversification of eIF4E in metazoans. We emphasise humans and two phylogenetically distant species which have become paradigms for studies on development, namely the fruit fly Drosophila melanogaster and the roundworm Caenorhabditis elegans.
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Affiliation(s)
- Greco Hernández
- mRNA and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), 22 San Fernando Ave., Tlalpan, Mexico City, 14080, Mexico
| | - Paula Vazquez-Pianzola
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, Berne, 3012, Switzerland
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6
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Kumari P, Sarovar Bhavesh N. Birth and death view of DNA, RNA, and proteins. Gene 2023; 883:147672. [PMID: 37506987 DOI: 10.1016/j.gene.2023.147672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/26/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023]
Abstract
The potential of cells to guide their genome and configure genes to express at a given time and in response to specific stimuli is pivotal to regulate cellular processes such as tissue differentiation, organogenesis, organismal development, homeostasis, and disease. In this review, we focus on the diverse mechanisms involved in DNA replication and its degradation, mRNA synthesis, and associated regulation such as RNA capping, splicing, tailing, and export. mRNA turnover including Decapping, deadenylation, RNA interference, and Nonsense mediated mRNA decay followed by protein translation, post-translational modification, and protein turnover. We highlight recent advances in understanding the complex series of molecular mechanisms responsible for the remarkable cellular regulatory mechanisms.
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Affiliation(s)
- Pooja Kumari
- Amity Institute of Biotechnology, Amity University Jharkhand, Ranchi, Jharkhand 834001, India.
| | - Neel Sarovar Bhavesh
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India.
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7
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Nishikawa M, Katsu K, Koinuma H, Hashimoto M, Neriya Y, Matsuyama J, Yamamoto T, Suzuki M, Matsumoto O, Matsui H, Nakagami H, Maejima K, Namba S, Yamaji Y. Interaction of EXA1 and eIF4E Family Members Facilitates Potexvirus Infection in Arabidopsis thaliana. J Virol 2023; 97:e0022123. [PMID: 37199623 PMCID: PMC10308960 DOI: 10.1128/jvi.00221-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 04/26/2023] [Indexed: 05/19/2023] Open
Abstract
Plant viruses depend on a number of host factors for successful infection. Deficiency of critical host factors confers recessively inherited viral resistance in plants. For example, loss of Essential for poteXvirus Accumulation 1 (EXA1) in Arabidopsis thaliana confers resistance to potexviruses. However, the molecular mechanism of how EXA1 assists potexvirus infection remains largely unknown. Previous studies reported that the salicylic acid (SA) pathway is upregulated in exa1 mutants, and EXA1 modulates hypersensitive response-related cell death during EDS1-dependent effector-triggered immunity. Here, we show that exa1-mediated viral resistance is mostly independent of SA and EDS1 pathways. We demonstrate that Arabidopsis EXA1 interacts with three members of the eukaryotic translation initiation factor 4E (eIF4E) family, eIF4E1, eIFiso4E, and novel cap-binding protein (nCBP), through the eIF4E-binding motif (4EBM). Expression of EXA1 in exa1 mutants restored infection by the potexvirus Plantago asiatica mosaic virus (PlAMV), but EXA1 with mutations in 4EBM only partially restored infection. In virus inoculation experiments using Arabidopsis knockout mutants, EXA1 promoted PlAMV infection in concert with nCBP, but the functions of eIFiso4E and nCBP in promoting PlAMV infection were redundant. By contrast, the promotion of PlAMV infection by eIF4E1 was, at least partially, EXA1 independent. Taken together, our results imply that the interaction of EXA1-eIF4E family members is essential for efficient PlAMV multiplication, although specific roles of three eIF4E family members in PlAMV infection differ. IMPORTANCE The genus Potexvirus comprises a group of plant RNA viruses, including viruses that cause serious damage to agricultural crops. We previously showed that loss of Essential for poteXvirus Accumulation 1 (EXA1) in Arabidopsis thaliana confers resistance to potexviruses. EXA1 may thus play a critical role in the success of potexvirus infection; hence, elucidation of its mechanism of action is crucial for understanding the infection process of potexviruses and for effective viral control. Previous studies reported that loss of EXA1 enhances plant immune responses, but our results indicate that this is not the primary mechanism of exa1-mediated viral resistance. Here, we show that Arabidopsis EXA1 assists infection by the potexvirus Plantago asiatica mosaic virus (PlAMV) by interacting with the eukaryotic translation initiation factor 4E family. Our results imply that EXA1 contributes to PlAMV multiplication by regulating translation.
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Affiliation(s)
- Masanobu Nishikawa
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Kosuke Katsu
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroaki Koinuma
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Masayoshi Hashimoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yutaro Neriya
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Juri Matsuyama
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Toya Yamamoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Masato Suzuki
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Oki Matsumoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Hidenori Matsui
- Graduate School of Environmental and Life Science, Okayama University, Okayama, Japan
| | | | - Kensaku Maejima
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Shigetou Namba
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yasuyuki Yamaji
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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8
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Palumbo RJ, Hanes SD. Catalytic activity of the Bin3/MEPCE methyltransferase domain is dispensable for 7SK snRNP function in Drosophila melanogaster. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.01.543302. [PMID: 37333392 PMCID: PMC10274667 DOI: 10.1101/2023.06.01.543302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Methylphosphate Capping Enzyme (MEPCE) monomethylates the gamma phosphate at the 5' end of the 7SK noncoding RNA, a modification thought to protect 7SK from degradation. 7SK serves as a scaffold for assembly of a snRNP complex that inhibits transcription by sequestering the positive elongation factor P-TEFb. While much is known about the biochemical activity of MEPCE in vitro, little is known about its functions in vivo, or what roles- if any-there are for regions outside the conserved methyltransferase domain. Here, we investigated the role of Bin3, the Drosophila ortholog of MEPCE, and its conserved functional domains in Drosophila development. We found that bin3 mutant females had strongly reduced rates of egg-laying, which was rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 promotes fecundity by repressing P-TEFb. bin3 mutants also exhibited neuromuscular defects, analogous to a patient with MEPCE haploinsufficiency. These defects were also rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 and MEPCE have conserved roles in promoting neuromuscular function by repressing P-TEFb. Unexpectedly, we found that a Bin3 catalytic mutant (Bin3Y795A) could still bind and stabilize 7SK and rescue all bin3 mutant phenotypes, indicating that Bin3 catalytic activity is dispensable for 7SK stability and snRNP function in vivo. Finally, we identified a metazoan-specific motif (MSM) outside of the methyltransferase domain and generated mutant flies lacking this motif (Bin3ΔMSM). Bin3ΔMSM mutant flies exhibited some-but not all-bin3 mutant phenotypes, suggesting that the MSM is required for a 7SK-independent, tissue-specific function of Bin3.
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Affiliation(s)
- Ryan J Palumbo
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University 750 East Adams Street, 4283 Weiskotten Hall, Syracuse, New York, 13210
| | - Steven D Hanes
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University 750 East Adams Street, 4283 Weiskotten Hall, Syracuse, New York, 13210
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9
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He S, Valkov E, Cheloufi S, Murn J. The nexus between RNA-binding proteins and their effectors. Nat Rev Genet 2023; 24:276-294. [PMID: 36418462 DOI: 10.1038/s41576-022-00550-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2022] [Indexed: 11/25/2022]
Abstract
RNA-binding proteins (RBPs) regulate essentially every event in the lifetime of an RNA molecule, from its production to its destruction. Whereas much has been learned about RNA sequence specificity and general functions of individual RBPs, the ways in which numerous RBPs instruct a much smaller number of effector molecules, that is, the core engines of RNA processing, as to where, when and how to act remain largely speculative. Here, we survey the known modes of communication between RBPs and their effectors with a particular focus on converging RBP-effector interactions and their roles in reducing the complexity of RNA networks. We discern the emerging unifying principles and discuss their utility in our understanding of RBP function, regulation of biological processes and contribution to human disease.
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Affiliation(s)
- Shiyang He
- Department of Biochemistry, University of California, Riverside, CA, USA
- Center for RNA Biology and Medicine, Riverside, CA, USA
| | - Eugene Valkov
- RNA Biology Laboratory & Center for Structural Biology, Center for Cancer Research, National Cancer Institute (NCI), Frederick, MD, USA
| | - Sihem Cheloufi
- Department of Biochemistry, University of California, Riverside, CA, USA.
- Center for RNA Biology and Medicine, Riverside, CA, USA.
- Stem Cell Center, University of California, Riverside, CA, USA.
| | - Jernej Murn
- Department of Biochemistry, University of California, Riverside, CA, USA.
- Center for RNA Biology and Medicine, Riverside, CA, USA.
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10
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Yang Z, Li X, Gan X, Wei M, Wang C, Yang G, Zhao Y, Zhu Z, Wang Z. Hydrogel armed with Bmp2 mRNA-enriched exosomes enhances bone regeneration. J Nanobiotechnology 2023; 21:119. [PMID: 37020301 PMCID: PMC10075167 DOI: 10.1186/s12951-023-01871-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 03/24/2023] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND Sustained release of bioactive BMP2 (bone morphogenetic protein-2) is important for bone regeneration, while the intrinsic short half-life of BMP2 at protein level cannot meet the clinical need. In this study, we aimed to design Bmp2 mRNA-enriched engineered exosomes, which were then loaded into specific hydrogel to achieve sustained release for more efficient and safe bone regeneration. RESULTS Bmp2 mRNA was enriched into exosomes by selective inhibition of translation in donor cells, in which NoBody (non-annotated P-body dissociating polypeptide, a protein that inhibits mRNA translation) and modified engineered BMP2 plasmids were co-transfected. The derived exosomes were named ExoBMP2+NoBody. In vitro experiments confirmed that ExoBMP2+NoBody had higher abundance of Bmp2 mRNA and thus stronger osteogenic induction capacity. When loaded into GelMA hydrogel via ally-L-glycine modified CP05 linker, the exosomes could be slowly released and thus ensure prolonged effect of BMP2 when endocytosed by the recipient cells. In the in vivo calvarial defect model, ExoBMP2+NoBody-loaded GelMA displayed great capacity in promoting bone regeneration. CONCLUSIONS Together, the proposed ExoBMP2+NoBody-loaded GelMA can provide an efficient and innovative strategy for bone regeneration.
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Affiliation(s)
- Zhujun Yang
- Department of Stomatology, Xi'an Central Hospital Affiliated to Xi'an Jiaotong University, Xi'an, 710003, Shaanxi, China
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China
- The State Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Xuejian Li
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China
| | - Xueqi Gan
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, 610041, Chengdu, China
| | - Mengying Wei
- The State Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Chunbao Wang
- College of Chemistry and Bio-Engineering, Yichun University, Yichun, 336000, Jiangxi, China
| | - Guodong Yang
- The State Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Yimin Zhao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
| | - Zhuoli Zhu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, 610041, Chengdu, China.
| | - Zhongshan Wang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
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11
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Korneeva N, Khalil MI, Ghosh I, Fan R, Arnold T, De Benedetti A. SARS-CoV-2 viral protein Nsp2 stimulates translation under normal and hypoxic conditions. Virol J 2023; 20:55. [PMID: 36998012 PMCID: PMC10060939 DOI: 10.1186/s12985-023-02021-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023] Open
Abstract
AbstractWhen viruses like SARS-CoV-2 infect cells, they reprogram the repertoire of cellular and viral transcripts that are being translated to optimize their strategy of replication, often targeting host translation initiation factors, particularly eIF4F complex consisting of eIF4E, eIF4G and eIF4A. A proteomic analysis of SARS-CoV-2/human proteins interaction revealed viral Nsp2 and initiation factor eIF4E2, but a role of Nsp2 in regulating translation is still controversial. HEK293T cells stably expressing Nsp2 were tested for protein synthesis rates of synthetic and endogenous mRNAs known to be translated via cap- or IRES-dependent mechanism under normal and hypoxic conditions. Both cap- and IRES-dependent translation were increased in Nsp2-expressing cells under normal and hypoxic conditions, especially mRNAs that require high levels of eIF4F. This could be exploited by the virus to maintain high translation rates of both viral and cellular proteins, particularly in hypoxic conditions as may arise in SARS-CoV-2 patients with poor lung functioning.
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12
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Layana C, Vilardo ES, Corujo G, Hernández G, Rivera-Pomar R. Drosophila Me31B is a Dual eIF4E-Interacting Protein. J Mol Biol 2023; 435:167949. [PMID: 36638908 DOI: 10.1016/j.jmb.2023.167949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/14/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
Eukaryotic translation initiation factor 4E (eIF4E) is a key factor involved in different aspects of mRNA metabolism. Drosophila melanogaster genome encodes eight eIF4E isoforms, and the canonical isoform eIF4E-1 is a ubiquitous protein that plays a key role in mRNA translation. eIF4E-3 is specifically expressed in testis and controls translation during spermatogenesis. In eukaryotic cells, translational control and mRNA decay is highly regulated in different cytoplasmic ribonucleoprotein foci, which include the processing bodies (PBs). In this study, we show that Drosophila eIF4E-1 and eIF4E-3 occur in PBs along the DEAD-box RNA helicase Me31B. We show that Me31B interacts with eIF4E-1 and eIF4E-3 by means of yeast two-hybrid system, FRET in D. melanogaster S2 cells and coimmunoprecipitation in testis. Truncation and point mutations of Me31B proteins show two eIF4E-binding sites located in different protein domains. Residues Y401-L407 (at the carboxy-terminus) are essential for interaction with eIF4E-1, whereas residues F63-L70 (at the amino-terminus) are critical for interaction with eIF4E-3. The residue W117 in eIF4E-1 and the homolog position F103 in eIF4E-3 are necessary for Me31B-eIF4E interaction suggesting that the change of tryptophan to phenylalanine provides specificity. Me31B represents a novel type of eIF4E-interacting protein with dual and specific interaction domains that might be recognized by different eIF4E isoforms in different tissues, adding complexity to the control of gene expression in eukaryotes.
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Affiliation(s)
- Carla Layana
- Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Boulevard 120 N° 1459, 1900 La Plata, Argentina.
| | - Emiliano Salvador Vilardo
- Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Boulevard 120 N° 1459, 1900 La Plata, Argentina
| | - Gonzalo Corujo
- Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Boulevard 120 N° 1459, 1900 La Plata, Argentina
| | - Greco Hernández
- Translation and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), 22 San Fernando Ave., Tlalpan, 14080 Mexico City, Mexico
| | - Rolando Rivera-Pomar
- Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Boulevard 120 N° 1459, 1900 La Plata, Argentina; Centro de Investigación y Transferencia del Noroeste de Buenos Aires (CITNOBA) - Centro de Bioinvestigaciones, Universidad Nacional del Noroeste de Buenos Aires, Av. Presidente Frondizi Km 4, 2700 Pergamino, Argentina; Molecular Developmental Biology Emeritus Group, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
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13
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Christie M, Igreja C. eIF4E-homologous protein (4EHP): a multifarious cap-binding protein. FEBS J 2023; 290:266-285. [PMID: 34758096 DOI: 10.1111/febs.16275] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/29/2021] [Accepted: 11/09/2021] [Indexed: 02/05/2023]
Abstract
The cap-binding protein 4EHP/eIF4E2 has been a recent object of interest in the field of post-transcriptional gene regulation and translational control. From ribosome-associated quality control, to RNA decay and microRNA-mediated gene silencing, this member of the eIF4E protein family regulates gene expression through numerous pathways. Low in abundance but ubiquitously expressed, 4EHP interacts with different binding partners to form multiple protein complexes that regulate translation in a variety of biological contexts. Documented functions of 4EHP primarily relate to its role as a translational repressor, but recent findings indicate that it might also participate in the activation of translation in specific settings. In this review, we discuss the known functions, properties and mechanisms that involve 4EHP in the control of gene expression. We also discuss our current understanding of how 4EHP processes are regulated in eukaryotic cells, and the diseases implicated with dysregulation of 4EHP-mediated translational control.
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Affiliation(s)
- Mary Christie
- School of Life and Environmental Sciences, The University of Sydney, NSW, Australia
| | - Cátia Igreja
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
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14
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Lehner MH, Walker J, Temcinaite K, Herlihy A, Taschner M, Berger AC, Corbett AH, Dirac Svejstrup AB, Svejstrup JQ. Yeast Smy2 and its human homologs GIGYF1 and -2 regulate Cdc48/VCP function during transcription stress. Cell Rep 2022; 41:111536. [PMID: 36288698 PMCID: PMC9638028 DOI: 10.1016/j.celrep.2022.111536] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 06/09/2022] [Accepted: 09/29/2022] [Indexed: 12/02/2022] Open
Abstract
The "last resort" pathway results in ubiquitylation and degradation of RNA polymerase II in response to transcription stress and is governed by factors such as Def1 in yeast. Here, we show that the SMY2 gene acts as a multi-copy suppressor of DEF1 deletion and functions at multiple steps of the last resort pathway. We also provide genetic and biochemical evidence from disparate cellular processes that Smy2 works more broadly as a hitherto overlooked regulator of Cdc48 function. Similarly, the Smy2 homologs GIGYF1 and -2 affect the transcription stress response in human cells and regulate the function of the Cdc48 homolog VCP/p97, presently being explored as a target for cancer therapy. Indeed, we show that the apoptosis-inducing effect of VCP inhibitors NMS-873 and CB-5083 is GIGYF1/2 dependent.
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Affiliation(s)
- Michelle Harreman Lehner
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Jane Walker
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Kotryna Temcinaite
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Anna Herlihy
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Michael Taschner
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Adam C Berger
- Department of Biology, RRC 1021, Emory University, 1510 Clifton Road, NE, Atlanta 30322, GA, USA
| | - Anita H Corbett
- Department of Biology, RRC 1021, Emory University, 1510 Clifton Road, NE, Atlanta 30322, GA, USA
| | - A Barbara Dirac Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.
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15
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Zou L, Moch C, Graille M, Chapat C. The SARS-CoV-2 protein NSP2 impairs the silencing capacity of the human 4EHP-GIGYF2 complex. iScience 2022; 25:104646. [PMID: 35756894 PMCID: PMC9213009 DOI: 10.1016/j.isci.2022.104646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/12/2022] [Accepted: 06/15/2022] [Indexed: 01/20/2023] Open
Abstract
There is an urgent need for a molecular understanding of how SARS-CoV-2 influences the machineries of the host cell. Herein, we focused our attention on the capacity of the SARS-CoV-2 protein NSP2 to bind the human 4EHP-GIGYF2 complex, a key factor involved in microRNA-mediated silencing of gene expression. Using in vitro interaction assays, our data demonstrate that NSP2 physically associates with both 4EHP and a central segment in GIGYF2 in the cytoplasm. We also provide functional evidence showing that NSP2 impairs the function of GIGYF2 in mediating translation repression using reporter-based assays. Collectively, these data reveal the potential impact of NSP2 on the post-transcriptional silencing of gene expression in human cells, pointing out 4EHP-GIGYF2 targeting as a possible strategy of SARS-CoV-2 to take over the silencing machinery and to suppress host defenses.
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Affiliation(s)
- Limei Zou
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris. F-91128 Palaiseau, France
| | - Clara Moch
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris. F-91128 Palaiseau, France
| | - Marc Graille
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris. F-91128 Palaiseau, France
| | - Clément Chapat
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris. F-91128 Palaiseau, France
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16
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Biziaev NS, Egorova TV, Alkalaeva EZ. Dynamics of Eukaryotic mRNA Structure during Translation. Mol Biol 2022. [DOI: 10.1134/s0026893322030037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Mammalian eIF4E2-GSK3β maintains basal phosphorylation of p53 to resist senescence under hypoxia. Cell Death Dis 2022; 13:459. [PMID: 35568694 PMCID: PMC9107480 DOI: 10.1038/s41419-022-04897-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 04/25/2022] [Accepted: 04/29/2022] [Indexed: 12/14/2022]
Abstract
Hypoxia modulates senescence, but their physiological link remains unclear. Here, we found that eIF4E2, a hypoxia-activated translation initiation factor, interacted with GSK3β to maintain phosphorylation of p53, thus resisting senescence under hypoxia. RNA-binding protein RBM38 interacted with eIF4E to inhibit the translation of p53, but GSK3β-mediated Ser195 phosphorylation disrupted the RBM38-eIF4E interaction. Through investigation of RBM38 phosphorylation, we found that the eIF4E2-GSK3β pathway specifically regulated proline-directed serine/threonine phosphorylation (S/T-P). Importantly, peptides e2-I or G3-I that blocking eIF4E2-GSK3β interaction can inhibit the basal S/T-P phosphorylation of p53 at multiple sites, therby inducing senescence through transcriptional inhibition. Additionally, a nanobody was screened via the domain where eIF4E2 bound to GSK3β, and this nanobody inhibited S/T-P phosphorylation to promote senescence. Furthermore, hypoxia inhibited eIF4E2-GSK3β pathway by mediating S-Nitrosylation of GSK3β. Blocking eIF4E2-GSK3β interaction promoted liver senescence under hypoxia, thus leading to liver fibrosis, eventually accelerating N, N-diethylnitrosamine (DEN)-induced tumorigenesis. Interestingly, eIF4E2 isoforms with GSK3β-binding motif exclusively exist in mammals, which protect zebrafish heart against hypoxia. Together, this study reveals a mammalian eIF4E2-GSK3β pathway that prevents senescence by maintaining basal S/T-P phosphorylation of p53, which underlies hypoxia adaptation of tissues.
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18
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Falk F, Kamanyi Marucha K, Clayton C. The EIF4E1-4EIP cap-binding complex of Trypanosoma brucei interacts with the terminal uridylyl transferase TUT3. PLoS One 2021; 16:e0258903. [PMID: 34807934 PMCID: PMC8608314 DOI: 10.1371/journal.pone.0258903] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 09/16/2021] [Indexed: 11/25/2022] Open
Abstract
Most transcription in Trypanosoma brucei is constitutive and polycistronic. Consequently, the parasite relies on post-transcriptional mechanisms, especially affecting translation initiation and mRNA decay, to control gene expression both at steady-state and for adaptation to different environments. The parasite has six isoforms of the cap-binding protein EIF4E as well as five EIF4Gs. EIF4E1 does not bind to any EIF4G, instead being associated with a 4E-binding protein, 4EIP. 4EIP represses translation and reduces the stability of a reporter mRNA when artificially tethered to the 3’-UTR, whether or not EIF4E1 is present. 4EIP is essential during the transition from the mammalian bloodstream form to the procyclic form that lives in the Tsetse vector. In contrast, EIF4E1 is dispensable during differentiation, but is required for establishment of growing procyclic forms. In Leishmania, there is some evidence that EIF4E1 might be active in translation initiation, via direct recruitment of EIF3. However in T. brucei, EIF4E1 showed no detectable association with other translation initiation factors, even in the complete absence of 4EIP. There was some evidence for interactions with NOT complex components, but if these occur they must be weak and transient. We found that EIF4E1is less abundant in the absence of 4EIP, and RNA pull-down results suggested this might occur through co-translational complex assembly. We also report that 4EIP directly recruits the cytosolic terminal uridylyl transferase TUT3 to EIF4E1/4EIP complexes. There was, however, no evidence that TUT3 is essential for 4EIP function.
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Affiliation(s)
- Franziska Falk
- DKFZ-ZMBH Alliance, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Kevin Kamanyi Marucha
- DKFZ-ZMBH Alliance, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Christine Clayton
- DKFZ-ZMBH Alliance, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
- * E-mail:
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19
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Chalkiadaki K, Statoulla E, Markou M, Bellou S, Bagli E, Fotsis T, Murphy C, Gkogkas CG. Translational control in neurovascular brain development. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211088. [PMID: 34659781 PMCID: PMC8511748 DOI: 10.1098/rsos.211088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
The human brain carries out complex tasks and higher functions and is crucial for organismal survival, as it senses both intrinsic and extrinsic environments. Proper brain development relies on the orchestrated development of different precursor cells, which will give rise to the plethora of mature brain cell-types. Within this process, neuronal cells develop closely to and in coordination with vascular cells (endothelial cells (ECs), pericytes) in a bilateral communication process that relies on neuronal activity, attractive or repulsive guidance cues for both cell types and on tight-regulation of gene expression. Translational control is a master regulator of the gene-expression pathway and in particular for neuronal and ECs, it can be localized in developmentally relevant (axon growth cone, endothelial tip cell) and mature compartments (synapses, axons). Herein, we will review mechanisms of translational control relevant to brain development in neurons and ECs in health and disease.
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Affiliation(s)
- Kleanthi Chalkiadaki
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Elpida Statoulla
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Maria Markou
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Sofia Bellou
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Eleni Bagli
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Theodore Fotsis
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Carol Murphy
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Christos G. Gkogkas
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
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20
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Mayya VK, Flamand MN, Lambert AM, Jafarnejad SM, Wohlschlegel JA, Sonenberg N, Duchaine TF. microRNA-mediated translation repression through GYF-1 and IFE-4 in C. elegans development. Nucleic Acids Res 2021; 49:4803-4815. [PMID: 33758928 PMCID: PMC8136787 DOI: 10.1093/nar/gkab162] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/24/2021] [Accepted: 03/17/2021] [Indexed: 12/11/2022] Open
Abstract
microRNA (miRNA)-mediated gene silencing is enacted through the recruitment of effector proteins that direct translational repression or degradation of mRNA targets, but the relative importance of their activities for animal development remains unknown. Our concerted proteomic surveys identified the uncharacterized GYF-domain encoding protein GYF-1 and its direct interaction with IFE-4, the ortholog of the mammalian translation repressor 4EHP, as key miRNA effector proteins in Caenorhabditis elegans. Recruitment of GYF-1 protein to mRNA reporters in vitro or in vivo leads to potent translation repression without affecting the poly(A) tail or impinging on mRNA stability. Loss of gyf-1 is synthetic lethal with hypomorphic alleles of embryonic miR-35-42 and larval (L4) let-7 miRNAs, which is phenocopied through engineered mutations in gyf-1 that abolish interaction with IFE-4. GYF-1/4EHP function is cascade-specific, as loss of gyf-1 had no noticeable impact on the functions of other miRNAs, including lin-4 and lsy-6. Overall, our findings reveal the first direct effector of miRNA-mediated translational repression in C. elegans and its physiological importance for the function of several, but likely not all miRNAs.
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Affiliation(s)
- Vinay K Mayya
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
| | - Mathieu N Flamand
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
| | - Alice M Lambert
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
| | - Seyed Mehdi Jafarnejad
- Patrick G. Johnston Centre for Cancer Research, Queen's University of Belfast, Belfast BT9 7AE UK
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Nahum Sonenberg
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
| | - Thomas F Duchaine
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
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21
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Gillen AE, Goering R, Taliaferro JM. Quantifying alternative polyadenylation in RNAseq data with LABRAT. Methods Enzymol 2021; 655:245-263. [PMID: 34183124 DOI: 10.1016/bs.mie.2021.03.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Alternative polyadenylation (APA) generates transcript isoforms that differ in their 3' UTR content and may therefore be subject to different regulatory fates. Although the existence of APA has been known for decades, quantification of APA isoforms from high-throughput RNA sequencing data has been difficult. To facilitate the study of APA in large datasets, we developed an APA quantification technique called LABRAT (Lightweight Alignment-Based Reckoning of Alternative Three-prime ends). LABRAT leverages modern transcriptome quantification approaches to determine the relative abundances of APA isoforms. In this manuscript we describe how LABRAT produces its calculations, provide a step-by-step protocol for its use, and demonstrate its ability to quantify APA in single-cell RNAseq data.
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Affiliation(s)
- Austin E Gillen
- Division of Hematology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Raeann Goering
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - J Matthew Taliaferro
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.
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22
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Baron N, Tupperwar N, Dahan I, Hadad U, Davidov G, Zarivach R, Shapira M. Distinct features of the Leishmania cap-binding protein LeishIF4E2 revealed by CRISPR-Cas9 mediated hemizygous deletion. PLoS Negl Trop Dis 2021; 15:e0008352. [PMID: 33760809 PMCID: PMC8021392 DOI: 10.1371/journal.pntd.0008352] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 04/05/2021] [Accepted: 02/15/2021] [Indexed: 01/08/2023] Open
Abstract
Leishmania parasites cycle between sand-fly vectors and mammalian hosts adapting to alternating environments by stage-differentiation accompanied by changes in the proteome profiles. Translation regulation plays a central role in driving the differential program of gene expression since control of gene regulation in Leishmania is mostly post-transcriptional. The Leishmania genome encodes six eIF4E paralogs, some of which bind a dedicated eIF4G candidate, and each eIF4E is assumed to have specific functions with perhaps some overlaps. However, LeishIF4E2 does not bind any known eIF4G ortholog and was previously shown to comigrate with the polysomal fractions of sucrose gradients in contrast to the other initiation factors that usually comigrate with pre-initiation and initiation complexes. Here we deleted one of the two LeishIF4E2 gene copies using the CRISPR-Cas9 methodology. The deletion caused severe alterations in the morphology of the mutant cells that became round, small, and equipped with a very short flagellum that did not protrude from its pocket. Reduced expression of LeishIF4E2 had no global effect on translation and growth, unlike other LeishIF4Es; however, there was a change in the proteome profile of the LeishIF4E2(+/-) cells. Upregulated proteins were related mainly to general metabolic processes including enzymes involved in fatty acid metabolism, DNA repair and replication, signaling, and cellular motor activity. The downregulated proteins included flagellar rod and cytoskeletal proteins, as well as surface antigens involved in virulence. Moreover, the LeishIF4E2(+/-) cells were impaired in their ability to infect cultured macrophages. Overall, LeishIF4E2 does not behave like a general translation factor and its function remains elusive. Our results also suggest that the individual LeishIF4Es perform unique functions. Leishmania parasites cause a broad spectrum of diseases with different pathological symptoms. During their life cycle the parasites shuffle between sand-fly vectors and mammalian hosts adapting to the changing environments via a stage specific program of gene expression that promotes their survival. Translation initiation plays a key role in control of gene expression and in Leishmania this is exemplified by the presence of multiple cap-binding complexes that interact with mRNAs. The parasites encode multiple paralogs of the cap-binding translation initiation factor eIF4E and of its corresponding binding partner eIF4G forming complexes with different potential functions. The role of LeishIF4E2 remains elusive: it does not bind any of the LeishIF4G candidate subunits and associates with polysomes, a feature less common for canonical translation factors. Here we generated a hemizygous Leishmania mutant of the least studied cap-binding paralog, LeishIF4E2, by eliminating one of the two alleles using the CRISPR-Cas9 methodology. The mutant showed morphological defects with short and rounded cells, and a significant reduction in their flagellar length. Moreover, the LeishIF4E2(+/-) cells were impaired in their ability to infect cultured macrophages. The mutants showed differences in their proteome: upregulated proteins were related mainly to general metabolic processes including enzymes involved in fatty acid metabolism, DNA repair and replication, signaling, and cellular motor activity. Downregulated proteins included flagellar rod and cytoskeletal proteins, as well as surface antigens involved in virulence. Overall, LeishIF4E2 does not behave like a general translation factor and its function remains elusive. It could affect translation of a particular set of transcripts, causing direct or downstream effects that do not affect global translation. Our results suggest that individual LeishIF4Es perform specific functions.
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Affiliation(s)
- Nofar Baron
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Nitin Tupperwar
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Irit Dahan
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Uzi Hadad
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Geula Davidov
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Raz Zarivach
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Michal Shapira
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- * E-mail:
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23
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microRNA-induced translational control of antiviral immunity by the cap-binding protein 4EHP. Mol Cell 2021; 81:1187-1199.e5. [PMID: 33581076 DOI: 10.1016/j.molcel.2021.01.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 12/14/2022]
Abstract
Type I interferons (IFNs) are critical cytokines in the host defense against invading pathogens. Sustained production of IFNs, however, is detrimental to the host, as it provokes autoimmune diseases. Thus, the expression of IFNs is tightly controlled. We report that the mRNA 5' cap-binding protein 4EHP plays a key role in regulating type I IFN concomitant with controlling virus replication, both in vitro and in vivo. Mechanistically, 4EHP suppresses IFN-β production by effecting the miR-34a-induced translational silencing of Ifnb1 mRNA. miR-34a is upregulated by both RNA virus infection and IFN-β induction, prompting a negative feedback regulatory mechanism that represses IFN-β expression via 4EHP. These findings demonstrate the direct involvement of 4EHP in virus-induced host response, underscoring a critical translational silencing mechanism mediated by 4EHP and miR-34a to impede sustained IFN production. This study highlights an intrinsic regulatory function for miRNA and the translation machinery in maintaining host homeostasis.
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Pelletier J, Schmeing TM, Sonenberg N. The multifaceted eukaryotic cap structure. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1636. [PMID: 33300197 DOI: 10.1002/wrna.1636] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/16/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022]
Abstract
The 5' cap structure is added onto RNA polymerase II transcripts soon after initiation of transcription and modulates several post-transcriptional regulatory events involved in RNA maturation. It is also required for stimulating translation initiation of many cytoplasmic mRNAs and serves to protect mRNAs from degradation. These functional properties of the cap are mediated by several cap binding proteins (CBPs) involved in nuclear and cytoplasmic gene expression steps. The role that CBPs play in gene regulation, as well as the biophysical nature by which they recognize the cap, is quite intricate. Differences in mechanisms of capping as well as nuances in cap recognition speak to the potential of targeting these processes for drug development. In this review, we focus on recent findings concerning the cap epitranscriptome, our understanding of cap binding by different CBPs, and explore therapeutic targeting of CBP-cap interaction. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Processing > Capping and 5' End Modifications Translation > Translation Mechanisms.
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Affiliation(s)
- Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Department of Oncology, McGill University, Montreal, Quebec, Canada.,Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Centre de Recherche en Biologie Structurale, McGill University, Montreal, Quebec, Canada
| | - T Martin Schmeing
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Centre de Recherche en Biologie Structurale, McGill University, Montreal, Quebec, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
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25
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Lee LJ, Papadopoli D, Jewer M, Del Rincon S, Topisirovic I, Lawrence MG, Postovit LM. Cancer Plasticity: The Role of mRNA Translation. Trends Cancer 2020; 7:134-145. [PMID: 33067172 PMCID: PMC8023421 DOI: 10.1016/j.trecan.2020.09.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/08/2020] [Accepted: 09/15/2020] [Indexed: 12/12/2022]
Abstract
Tumor progression is associated with dedifferentiated histopathologies concomitant with cancer cell survival within a changing, and often hostile, tumor microenvironment. These processes are enabled by cellular plasticity, whereby intracellular cues and extracellular signals are integrated to enable rapid shifts in cancer cell phenotypes. Cancer cell plasticity, at least in part, fuels tumor heterogeneity and facilitates metastasis and drug resistance. Protein synthesis is frequently dysregulated in cancer, and emerging data suggest that translational reprograming collaborates with epigenetic and metabolic programs to effectuate phenotypic plasticity of neoplasia. Herein, we discuss the potential role of mRNA translation in cancer cell plasticity, highlight emerging histopathological correlates, and deliberate on how this is related to efforts to improve understanding of the complex tumor ecology.
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Affiliation(s)
- Laura J Lee
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
| | - David Papadopoli
- Lady Davis Institute, Gerald Bronfman Department of Oncology and Departments of Biochemistry and Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Michael Jewer
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
| | - Sonia Del Rincon
- Lady Davis Institute, Gerald Bronfman Department of Oncology and Departments of Biochemistry and Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Ivan Topisirovic
- Lady Davis Institute, Gerald Bronfman Department of Oncology and Departments of Biochemistry and Experimental Medicine, McGill University, Montreal, QC, Canada.
| | - Mitchell G Lawrence
- Biomedicine Discovery Institute Cancer Program, Prostate Cancer Research Group, Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC 3010, Australia.
| | - Lynne-Marie Postovit
- Department of Oncology, University of Alberta, Edmonton, AB, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
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26
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A cellular handbook for collided ribosomes: surveillance pathways and collision types. Curr Genet 2020; 67:19-26. [PMID: 33044589 DOI: 10.1007/s00294-020-01111-w] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 09/12/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022]
Abstract
Translating ribosomes slow down or completely stall when they encounter obstacles on mRNAs. Such events can lead to ribosomes colliding with each other and forming complexes of two (disome), three (trisome) or more ribosomes. While these events can activate surveillance pathways, it has been unclear if collisions are common on endogenous mRNAs and whether they are usually detected by these cellular pathways. Recent genome-wide surveys of collisions revealed widespread distribution of disomes and trisomes across endogenous mRNAs in eukaryotic cells. Several studies further hinted that the recognition of collisions and response to them by multiple surveillance pathways depend on the context and duration of the ribosome stalling. This review considers recent efforts in the identification of endogenous ribosome collisions and cellular pathways dedicated to sense their severity. We further discuss the potential role of collided ribosomes in modulating co-translational events and contributing to cellular homeostasis.
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Criscuolo S, Gatti Iou M, Merolla A, Maragliano L, Cesca F, Benfenati F. Engineering REST-Specific Synthetic PUF Proteins to Control Neuronal Gene Expression: A Combined Experimental and Computational Study. ACS Synth Biol 2020; 9:2039-2054. [PMID: 32678979 DOI: 10.1021/acssynbio.0c00119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Regulation of gene transcription is an essential mechanism for differentiation and adaptation of organisms. A key actor in this regulation process is the repressor element 1 (RE1)-silencing transcription factor (REST), a transcriptional repressor that controls more than 2000 putative target genes, most of which are neuron-specific. With the purpose of modulating REST expression, we exploited synthetic, ad hoc designed, RNA binding proteins (RBPs) able to specifically target and dock to REST mRNA. Among the various families of RBPs, we focused on the Pumilio and FBF (PUF) proteins, present in all eukaryotic organisms and controlling a variety of cellular functions. Here, a combined experimental and computational approach was used to design and test 8- and 16-repeat PUF proteins specific for REST mRNA. We explored the conformational properties and atomic features of the PUF-RNA recognition code by Molecular Dynamics simulations. Biochemical assays revealed that the 8- and 16-repeat PUF-based variants specifically bind the endogenous REST mRNA without affecting its translational regulation. The data also indicate a key role of stacking residues in determining the binding specificity. The newly characterized REST-specific PUF-based constructs act as excellent RNA-binding modules and represent a versatile and functional platform to specifically target REST mRNA and modulate its endogenous expression.
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Affiliation(s)
- Stefania Criscuolo
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova 16132, Italy
| | - Mahad Gatti Iou
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova 16132, Italy
| | - Assunta Merolla
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova 16132, Italy
- University of Genova, Genova 16132, Italy
| | - Luca Maragliano
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova 16132, Italy
- IRCCS Ospedale Policlinico San Martino, Genova 16132, Italy
| | - Fabrizia Cesca
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova 16132, Italy
- Department of Life Sciences, University of Trieste, Trieste 34127, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova 16132, Italy
- IRCCS Ospedale Policlinico San Martino, Genova 16132, Italy
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28
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Liu J, Liu F. The Yin and Yang function of microRNAs in insulin signalling and cancer. RNA Biol 2020; 18:24-32. [PMID: 32746694 DOI: 10.1080/15476286.2020.1804236] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Data accumulated over the past several decades uncover a vital role of microRNAs (miRNAs) in various biological processes. It is well established that, by binding to target mRNAs, miRNAs act as post-transcription suppressors to inhibit mRNA translation and/or to promote mRNA degradation. Very recently, miRNAs have been found to act as positive regulators to promote gene transcription. In this review, we briefly summarize the regulation and functional roles of miRNAs in metabolic diseases and cancer development. We also review recent advances on the mechanisms by which miRNAs regulate gene expression, focusing on their unconventional roles as enhancers to promote gene expression. Given the high potential of miRNAs as biomarkers for risk assessment and as high-value targets for therapy, a better understanding of the Yin-Yang functional feature of miRNAs and their mechanisms of action could have significant clinical implications for the treatment of various diseases such as obesity, type 2 diabetes, and cancer.
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Affiliation(s)
- Juanhong Liu
- National Clinical Research Center for Metabolic Diseases, and Metabolic Syndrome Research Center, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University , Changsha, China
| | - Feng Liu
- National Clinical Research Center for Metabolic Diseases, and Metabolic Syndrome Research Center, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University , Changsha, China.,Departments of Pharmacology, University of Texas Health at San Antonio , San Antonio, TX, USA
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29
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Huggins HP, Keiper BD. Regulation of Germ Cell mRNPs by eIF4E:4EIP Complexes: Multiple Mechanisms, One Goal. Front Cell Dev Biol 2020; 8:562. [PMID: 32733883 PMCID: PMC7358283 DOI: 10.3389/fcell.2020.00562] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 06/15/2020] [Indexed: 11/29/2022] Open
Abstract
Translational regulation of mRNAs is critically important for proper gene expression in germ cells, gametes, and embryos. The ability of the nucleus to control gene expression in these systems may be limited due to spatial or temporal constraints, as well as the breadth of gene products they express to prepare for the rapid animal development that follows. During development germ granules are hubs of post-transcriptional regulation of mRNAs. They assemble and remodel messenger ribonucleoprotein (mRNP) complexes for translational repression or activation. Recently, mRNPs have been appreciated as discrete regulatory units, whose function is dictated by the many positive and negative acting factors within the complex. Repressed mRNPs must be activated for translation on ribosomes to introduce novel proteins into germ cells. The binding of eIF4E to interacting proteins (4EIPs) that sequester it represents a node that controls many aspects of mRNP fate including localization, stability, poly(A) elongation, deadenylation, and translational activation/repression. Furthermore, plants and animals have evolved to express multiple functionally distinct eIF4E and 4EIP variants within germ cells, giving rise to different modes of translational regulation.
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Affiliation(s)
- Hayden P Huggins
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Brett D Keiper
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
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30
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Juszkiewicz S, Slodkowicz G, Lin Z, Freire-Pritchett P, Peak-Chew SY, Hegde RS. Ribosome collisions trigger cis-acting feedback inhibition of translation initiation. eLife 2020; 9:e60038. [PMID: 32657267 PMCID: PMC7381030 DOI: 10.7554/elife.60038] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/10/2020] [Indexed: 12/19/2022] Open
Abstract
Translation of aberrant mRNAs can cause ribosomes to stall, leading to collisions with trailing ribosomes. Collided ribosomes are specifically recognised by ZNF598 to initiate protein and mRNA quality control pathways. Here we found using quantitative proteomics of collided ribosomes that EDF1 is a ZNF598-independent sensor of ribosome collisions. EDF1 stabilises GIGYF2 at collisions to inhibit translation initiation in cis via 4EHP. The GIGYF2 axis acts independently of the ZNF598 axis, but each pathway's output is more pronounced without the other. We propose that the widely conserved and highly abundant EDF1 monitors the transcriptome for excessive ribosome density, then triggers a GIGYF2-mediated response to locally and temporarily reduce ribosome loading. Only when collisions persist is translation abandoned to initiate ZNF598-dependent quality control. This tiered response to ribosome collisions would allow cells to dynamically tune translation rates while ensuring fidelity of the resulting protein products.
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Affiliation(s)
- Szymon Juszkiewicz
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Greg Slodkowicz
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Zhewang Lin
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | | | - Sew-Yeu Peak-Chew
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Ramanujan S Hegde
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
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31
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Abstract
The stage at which ribosomes are recruited to messenger RNAs (mRNAs) is an elaborate and highly regulated phase of protein synthesis. Upon completion of this step, a ribosome is positioned at an appropriate initiation codon and primed to synthesize the encoded polypeptide product. In most circumstances, this step commits the ribosome to translate the mRNA. We summarize the knowledge regarding the initiation factors implicated in this activity as well as review different mechanisms by which this process is conducted.
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Affiliation(s)
- Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada; , .,Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec H3A 1A3, Canada.,Department of Oncology, McGill University, Montreal, Quebec H4A 3T2, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada; , .,Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec H3A 1A3, Canada
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32
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Lasko P. Patterning the Drosophila embryo: A paradigm for RNA-based developmental genetic regulation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1610. [PMID: 32543002 PMCID: PMC7583483 DOI: 10.1002/wrna.1610] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/13/2020] [Accepted: 05/17/2020] [Indexed: 12/16/2022]
Abstract
Embryonic anterior–posterior patterning is established in Drosophila melanogaster by maternally expressed genes. The mRNAs of several of these genes accumulate at either the anterior or posterior pole of the oocyte via a number of mechanisms. Many of these mRNAs are also under elaborate translational regulation. Asymmetric RNA localization coupled with spatially restricted translation ensures that their proteins are restricted to the position necessary for the developmental process that they drive. Bicoid (Bcd), the anterior determinant, and Oskar (Osk), the determinant for primordial germ cells and posterior patterning, have been studied particularly closely. In early embryos an anterior–posterior gradient of Bcd is established, activating transcription of different sets of zygotic genes depending on local Bcd concentration. At the posterior pole, Osk seeds formation of polar granules, ribonucleoprotein complexes that accumulate further mRNAs and proteins involved in posterior patterning and germ cell specification. After fertilization, polar granules associate with posterior nuclei and mature into nuclear germ granules. Osk accumulates in these granules, and either by itself or as part of the granules, stimulates germ cell division. This article is categorized under:RNA Export and Localization > RNA Localization Translation > Translation Regulation RNA in Disease and Development > RNA in Development
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Affiliation(s)
- Paul Lasko
- Department of Biology, McGill University, Montréal, Québec, Canada.,Department of Human Genetics, Radboudumc, Nijmegen, Netherlands
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33
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eIF4E and Interactors from Unicellular Eukaryotes. Int J Mol Sci 2020; 21:ijms21062170. [PMID: 32245232 PMCID: PMC7139794 DOI: 10.3390/ijms21062170] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/12/2020] [Accepted: 03/18/2020] [Indexed: 12/22/2022] Open
Abstract
eIF4E, the mRNA cap-binding protein, is well known as a general initiation factor allowing for mRNA-ribosome interaction and cap-dependent translation in eukaryotic cells. In this review we focus on eIF4E and its interactors in unicellular organisms such as yeasts and protozoan eukaryotes. In a first part, we describe eIF4Es from yeast species such as Saccharomyces cerevisiae, Candida albicans, and Schizosaccharomyces pombe. In the second part, we will address eIF4E and interactors from parasite unicellular species—trypanosomatids and marine microorganisms—dinoflagellates. We propose that different strategies have evolved during evolution to accommodate cap-dependent translation to differing requirements. These evolutive “adjustments” involve various forms of eIF4E that are not encountered in all microorganismic species. In yeasts, eIF4E interactors, particularly p20 and Eap1 are found exclusively in Saccharomycotina species such as S. cerevisiae and C. albicans. For protozoan parasites of the Trypanosomatidae family beside a unique cap4-structure located at the 5′UTR of all mRNAs, different eIF4Es and eIF4Gs are active depending on the life cycle stage of the parasite. Additionally, an eIF4E-interacting protein has been identified in Leishmania major which is important for switching from promastigote to amastigote stages. For dinoflagellates, little is known about the structure and function of the multiple and diverse eIF4Es that have been identified thanks to widespread sequencing in recent years.
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34
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Jaud M, Philippe C, Di Bella D, Tang W, Pyronnet S, Laurell H, Mazzolini L, Rouault-Pierre K, Touriol C. Translational Regulations in Response to Endoplasmic Reticulum Stress in Cancers. Cells 2020; 9:cells9030540. [PMID: 32111004 PMCID: PMC7140484 DOI: 10.3390/cells9030540] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/18/2020] [Accepted: 02/24/2020] [Indexed: 12/20/2022] Open
Abstract
During carcinogenesis, almost all the biological processes are modified in one way or another. Among these biological processes affected, anomalies in protein synthesis are common in cancers. Indeed, cancer cells are subjected to a wide range of stresses, which include physical injuries, hypoxia, nutrient starvation, as well as mitotic, oxidative or genotoxic stresses. All of these stresses will cause the accumulation of unfolded proteins in the Endoplasmic Reticulum (ER), which is a major organelle that is involved in protein synthesis, preservation of cellular homeostasis, and adaptation to unfavourable environment. The accumulation of unfolded proteins in the endoplasmic reticulum causes stress triggering an unfolded protein response in order to promote cell survival or to induce apoptosis in case of chronic stress. Transcription and also translational reprogramming are tightly controlled during the unfolded protein response to ensure selective gene expression. The majority of stresses, including ER stress, induce firstly a decrease in global protein synthesis accompanied by the induction of alternative mechanisms for initiating the translation of mRNA, later followed by a translational recovery. After a presentation of ER stress and the UPR response, we will briefly present the different modes of translation initiation, then address the specific translational regulatory mechanisms acting during reticulum stress in cancers and highlight the importance of translational control by ER stress in tumours.
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Affiliation(s)
- Manon Jaud
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
| | - Céline Philippe
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Doriana Di Bella
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Weiwei Tang
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Stéphane Pyronnet
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
| | - Henrik Laurell
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
- Inserm UMR1048, I2MC (Institut des Maladies Métaboliques et Cardiovasculaires), BP 84225, CEDEX 04, 31 432 Toulouse, France
| | - Laurent Mazzolini
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- CNRS ERL5294, CRCT, F-31037 Toulouse, France
| | - Kevin Rouault-Pierre
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Christian Touriol
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
- Correspondence:
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35
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Wang X, Voronina E. Diverse Roles of PUF Proteins in Germline Stem and Progenitor Cell Development in C. elegans. Front Cell Dev Biol 2020; 8:29. [PMID: 32117964 PMCID: PMC7015873 DOI: 10.3389/fcell.2020.00029] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/14/2020] [Indexed: 01/05/2023] Open
Abstract
Stem cell development depends on post-transcriptional regulation mediated by RNA-binding proteins (RBPs) (Zhang et al., 1997; Forbes and Lehmann, 1998; Okano et al., 2005; Ratti et al., 2006; Kwon et al., 2013). Pumilio and FBF (PUF) family RBPs are highly conserved post-transcriptional regulators that are critical for stem cell maintenance (Wickens et al., 2002; Quenault et al., 2011). The RNA-binding domains of PUF proteins recognize a family of related sequence motifs in the target mRNAs, yet individual PUF proteins have clearly distinct biological functions (Lu et al., 2009; Wang et al., 2018). The C. elegans germline is a simple and powerful model system for analyzing regulation of stem cell development. Studies in C. elegans uncovered specific physiological roles for PUFs expressed in the germline stem cells ranging from control of proliferation and differentiation to regulation of the sperm/oocyte decision. Importantly, recent studies started to illuminate the mechanisms behind PUF functional divergence. This review summarizes the many roles of PUF-8, FBF-1, and FBF-2 in germline stem and progenitor cells (SPCs) and discusses the factors accounting for their distinct biological functions. PUF proteins are conserved in evolution, and insights into PUF-mediated regulation provided by the C. elegans model system are likely relevant for other organisms.
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Affiliation(s)
- Xiaobo Wang
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Ekaterina Voronina
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
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36
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Ruscica V, Bawankar P, Peter D, Helms S, Igreja C, Izaurralde E. Direct role for the Drosophila GIGYF protein in 4EHP-mediated mRNA repression. Nucleic Acids Res 2020; 47:7035-7048. [PMID: 31114929 PMCID: PMC6648886 DOI: 10.1093/nar/gkz429] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/02/2019] [Accepted: 05/08/2019] [Indexed: 02/07/2023] Open
Abstract
The eIF4E-homologous protein (4EHP) is a translational repressor that competes with eIF4E for binding to the 5'-cap structure of specific mRNAs, to which it is recruited by protein factors such as the GRB10-interacting GYF (glycine-tyrosine-phenylalanine domain) proteins (GIGYF). Several experimental evidences suggest that GIGYF proteins are not merely facilitating 4EHP recruitment to transcripts but are actually required for the repressor activity of the complex. However, the underlying molecular mechanism is unknown. Here, we investigated the role of the uncharacterized Drosophila melanogaster (Dm) GIGYF protein in post-transcriptional mRNA regulation. We show that, when in complex with 4EHP, Dm GIGYF not only elicits translational repression but also promotes target mRNA decay via the recruitment of additional effector proteins. We identified the RNA helicase Me31B/DDX6, the decapping activator HPat and the CCR4-NOT deadenylase complex as binding partners of GIGYF proteins. Recruitment of Me31B and HPat via discrete binding motifs conserved among metazoan GIGYF proteins is required for downregulation of mRNA expression by the 4EHP-GIGYF complex. Our findings are consistent with a model in which GIGYF proteins additionally recruit decapping and deadenylation complexes to 4EHP-containing RNPs to induce translational repression and degradation of mRNA targets.
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Affiliation(s)
- Vincenzo Ruscica
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Praveen Bawankar
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany.,Institute of Molecular Biology gGmbH, Ackermannweg 4, 55128 Mainz, Germany
| | - Daniel Peter
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany.,European Molecular Biology Laboratory, 71 avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Sigrun Helms
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Cátia Igreja
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Elisa Izaurralde
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
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Communication Is Key: 5'-3' Interactions that Regulate mRNA Translation and Turnover. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:149-164. [PMID: 31811634 DOI: 10.1007/978-3-030-31434-7_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Most eukaryotic mRNAs maintain a 5' cap structure and 3' poly(A) tail, cis-acting elements that are often separated by thousands of nucleotides. Nevertheless, multiple paradigms exist where mRNA 5' and 3' termini interact with each other in order to regulate mRNA translation and turnover. mRNAs recruit translation initiation factors to their termini, which in turn physically interact with each other. This physical bridging of the mRNA termini is known as the "closed loop" model, with years of genetic and biochemical evidence supporting the functional synergy between the 5' cap and 3' poly(A) tail to enhance mRNA translation initiation. However, a number of examples exist of "non-canonical" 5'-3' communication for cellular and viral RNAs that lack 5' cap structures and/or poly(A) tails. Moreover, in several contexts, mRNA 5'-3' communication can function to repress translation. Overall, we detail how various mRNA 5'-3' interactions play important roles in posttranscriptional regulation, wherein depending on the protein factors involved can result in translational stimulation or repression.
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38
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Flora P, Wong-Deyrup SW, Martin ET, Palumbo RJ, Nasrallah M, Oligney A, Blatt P, Patel D, Fuchs G, Rangan P. Sequential Regulation of Maternal mRNAs through a Conserved cis-Acting Element in Their 3' UTRs. Cell Rep 2019; 25:3828-3843.e9. [PMID: 30590052 PMCID: PMC6328254 DOI: 10.1016/j.celrep.2018.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/28/2018] [Accepted: 11/30/2018] [Indexed: 12/31/2022] Open
Abstract
Maternal mRNAs synthesized during oogenesis initiate the development of future generations. Some maternal mRNAs are either somatic or germline determinants and must be translationally repressed until embryogenesis. However, the translational repressors themselves are temporally regulated. We used polar granule component (pgc), a Drosophila maternal mRNA, to ask how maternal transcripts are repressed while the regulatory landscape is shifting. pgc, a germline determinant, is translationally regulated throughout oogenesis. We find that different conserved RNA-binding proteins bind a 10-nt sequence in the 3′ UTR of pgc mRNA to continuously repress translation at different stages of oogenesis. Pumilio binds to this sequence in undifferentiated and early-differentiating oocytes to block Pgc translation. After differentiation, Bruno levels increase, allowing Bruno to bind the same sequence and take over translational repression of pgc mRNA. We have identified a class of maternal mRNAs that are regulated similarly, including zelda, the activator of the zygotic genome. Flora et al. show that pgc, a germline determinant, is translationally regulated throughout oogenesis. Different conserved RBPs bind a 10-nt sequence in the 3′ UTR to continuously repress translation throughout oogenesis. This mode of regulation applies to a class of maternal mRNAs, including zelda, the activator of the zygotic genome.
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Affiliation(s)
- Pooja Flora
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Siu Wah Wong-Deyrup
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Elliot Todd Martin
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Ryan J Palumbo
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Mohamad Nasrallah
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Andrew Oligney
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Patrick Blatt
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Dhruv Patel
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Gabriele Fuchs
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA.
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39
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Peter D, Ruscica V, Bawankar P, Weber R, Helms S, Valkov E, Igreja C, Izaurralde E. Molecular basis for GIGYF-Me31B complex assembly in 4EHP-mediated translational repression. Genes Dev 2019; 33:1355-1360. [PMID: 31439631 PMCID: PMC6771390 DOI: 10.1101/gad.329219.119] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 07/18/2019] [Indexed: 11/24/2022]
Abstract
In this study, Peter et al. provide new insights into how GIGYF proteins function together with DDX6 in the regulation of mRNA expression. They used structural analysis, in vivo expression analysis, and biochemical assays to show that GIGYF contains a motif that is necessary and sufficient for direct interaction with Me31B/DDX6, and their findings advance our understanding of the mechanism and assembly of the 4EHP–GIGYF–DDX6 repressor complex. GIGYF (Grb10-interacting GYF [glycine–tyrosine–phenylalanine domain]) proteins coordinate with 4EHP (eIF4E [eukaryotic initiation factor 4E] homologous protein), the DEAD (Asp–Glu–Ala–Asp)-box helicase Me31B/DDX6, and mRNA-binding proteins to elicit transcript-specific repression. However, the underlying molecular mechanism remains unclear. Here, we report that GIGYF contains a motif necessary and sufficient for direct interaction with Me31B/DDX6. A 2.4 Å crystal structure of the GIGYF–Me31B complex reveals that this motif arranges into a coil connected to a β hairpin on binding to conserved hydrophobic patches on the Me31B RecA2 domain. Structure-guided mutants indicate that 4EHP–GIGYF–DDX6 complex assembly is required for tristetraprolin-mediated down-regulation of an AU-rich mRNA, thus revealing the molecular principles of translational repression.
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Affiliation(s)
- Daniel Peter
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.,European Molecular Biology Laboratory, 38042 Grenoble Cedex 9, France
| | - Vincenzo Ruscica
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Praveen Bawankar
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.,Institute of Molecular Biology, 55128 Mainz, Germany
| | - Ramona Weber
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Sigrun Helms
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Eugene Valkov
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Cátia Igreja
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Elisa Izaurralde
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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40
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Proud CG. Phosphorylation and Signal Transduction Pathways in Translational Control. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033050. [PMID: 29959191 DOI: 10.1101/cshperspect.a033050] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protein synthesis, including the translation of specific messenger RNAs (mRNAs), is regulated by extracellular stimuli such as hormones and by the levels of certain nutrients within cells. This control involves several well-understood signaling pathways and protein kinases, which regulate the phosphorylation of proteins that control the translational machinery. These pathways include the mechanistic target of rapamycin complex 1 (mTORC1), its downstream effectors, and the mitogen-activated protein (MAP) kinase (extracellular ligand-regulated kinase [ERK]) signaling pathway. This review describes the regulatory mechanisms that control translation initiation and elongation factors, in particular the effects of phosphorylation on their interactions or activities. It also discusses current knowledge concerning the impact of these control systems on the translation of specific mRNAs or subsets of mRNAs, both in physiological processes and in diseases such as cancer.
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Affiliation(s)
- Christopher G Proud
- Nutrition & Metabolism, South Australian Health & Medical Research Institute, North Terrace, Adelaide SA5000, Australia; and School of Biological Sciences, University of Adelaide, Adelaide SA5000, Australia
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41
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Terrao M, Marucha KK, Mugo E, Droll D, Minia I, Egler F, Braun J, Clayton C. The suppressive cap-binding complex factor 4EIP is required for normal differentiation. Nucleic Acids Res 2019; 46:8993-9010. [PMID: 30124912 PMCID: PMC6158607 DOI: 10.1093/nar/gky733] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/01/2018] [Indexed: 12/27/2022] Open
Abstract
Trypanosoma brucei live in mammals as bloodstream forms and in the Tsetse midgut as procyclic forms. Differentiation from one form to the other proceeds via a growth-arrested stumpy form with low messenger RNA (mRNA) content and translation. The parasites have six eIF4Es and five eIF4Gs. EIF4E1 pairs with the mRNA-binding protein 4EIP but not with any EIF4G. EIF4E1 and 4EIP each inhibit expression when tethered to a reporter mRNA, but while tethered EIF4E1 suppresses only when 4EIP is present, suppression by tethered 4EIP does not require the interaction with EIF4E1. In growing bloodstream forms, 4EIP is preferentially associated with unstable mRNAs. Bloodstream- or procyclic-form trypanosomes lacking 4EIP have only a marginal growth disadvantage. Bloodstream forms without 4EIP are, however, defective in translation suppression during stumpy-form differentiation and cannot subsequently convert to growing procyclic forms. Intriguingly, the differentiation defect can be complemented by a truncated 4EIP that does not interact with EIF4E1. In contrast, bloodstream forms lacking EIF4E1 have a growth defect, stumpy formation seems normal, but they appear unable to grow as procyclic forms. We suggest that 4EIP and EIF4E1 fine-tune mRNA levels in growing cells, and that 4EIP contributes to translation suppression during differentiation to the stumpy form.
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Affiliation(s)
- Monica Terrao
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Kevin K Marucha
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Elisha Mugo
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Dorothea Droll
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Igor Minia
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Franziska Egler
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Johanna Braun
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
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42
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A threonyl-tRNA synthetase-mediated translation initiation machinery. Nat Commun 2019; 10:1357. [PMID: 30902983 PMCID: PMC6430810 DOI: 10.1038/s41467-019-09086-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 02/13/2019] [Indexed: 12/13/2022] Open
Abstract
A fundamental question in biology is how vertebrates evolved and differ from invertebrates, and little is known about differences in the regulation of translation in the two systems. Herein, we identify a threonyl-tRNA synthetase (TRS)-mediated translation initiation machinery that specifically interacts with eIF4E homologous protein, and forms machinery that is structurally analogous to the eIF4F-mediated translation initiation machinery via the recruitment of other translation initiation components. Biochemical and RNA immunoprecipitation analyses coupled to sequencing suggest that this machinery emerged as a gain-of-function event in the vertebrate lineage, and it positively regulates the translation of mRNAs required for vertebrate development. Collectively, our findings demonstrate that TRS evolved to regulate vertebrate translation initiation via its dual role as a scaffold for the assembly of initiation components and as a selector of target mRNAs. This work highlights the functional significance of aminoacyl-tRNA synthetases in the emergence and control of higher order organisms. The initiation of translation is a highly regulated process that contributes to specific gene expression programs. Here the authors find that, in vertebrate, threonyl-tRNA synthetase (TRS) can act as a scaffold for the initiation machinery to stimulate the translation of a specific set of mRNAs.
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43
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Duchaine TF, Fabian MR. Mechanistic Insights into MicroRNA-Mediated Gene Silencing. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032771. [PMID: 29959194 DOI: 10.1101/cshperspect.a032771] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) posttranscriptionally regulate gene expression by repressing protein synthesis and exert a broad influence over development, physiology, adaptation, and disease. Over the past two decades, great strides have been made toward elucidating how miRNAs go about shutting down messenger RNA (mRNA) translation and promoting mRNA decay.
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Affiliation(s)
- Thomas F Duchaine
- Department of Biochemistry & Goodman Cancer Research Centre, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Marc R Fabian
- Department of Oncology, McGill University, Montreal, Quebec H3G 1Y6, Canada.,Lady Davis Institute, Jewish General Hospital, Montreal, Quebec H3T 1E2, Canada
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44
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Mayya VK, Duchaine TF. Ciphers and Executioners: How 3'-Untranslated Regions Determine the Fate of Messenger RNAs. Front Genet 2019; 10:6. [PMID: 30740123 PMCID: PMC6357968 DOI: 10.3389/fgene.2019.00006] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/07/2019] [Indexed: 12/29/2022] Open
Abstract
The sequences and structures of 3'-untranslated regions (3'UTRs) of messenger RNAs govern their stability, localization, and expression. 3'UTR regulatory elements are recognized by a wide variety of trans-acting factors that include microRNAs (miRNAs), their associated machinery, and RNA-binding proteins (RBPs). In turn, these factors instigate common mechanistic strategies to execute the regulatory programs encoded by 3'UTRs. Here, we review classes of factors that recognize 3'UTR regulatory elements and the effector machineries they guide toward mRNAs to dictate their expression and fate. We outline illustrative examples of competitive, cooperative, and coordinated interplay such as mRNA localization and localized translation. We further review the recent advances in the study of mRNP granules and phase transition, and their possible significance for the functions of 3'UTRs. Finally, we highlight some of the most recent strategies aimed at deciphering the complexity of the regulatory codes of 3'UTRs, and identify some of the important remaining challenges.
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Affiliation(s)
| | - Thomas F. Duchaine
- Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, QC, Canada
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45
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Baumgartner S. Seeing is believing: the Bicoid protein reveals its path. Hereditas 2018; 155:28. [PMID: 30220899 PMCID: PMC6134762 DOI: 10.1186/s41065-018-0067-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/04/2018] [Indexed: 11/30/2022] Open
Abstract
In this commentary, I will review the latest findings on the Bicoid (Bcd) morphogen in Drosophila, a paradigm for gradient formation taught to biology students for more than two decades. “Seeing is believing” also summarizes the erroneous steps that were needed to elucidate the mechanisms of gradient formation and the path of movement of Bcd. Initially proclaimed as a dogma in 1988 and later incorporated into the SDD model where the broad diffusion of Bcd throughout the embryo was the predominant step leading to gradient formation, the SDD model was irrefutable for more than two decades until first doubts were raised in 2007 regarding the diffusion properties of Bcd associated with the SDD model. This led to re-thinking of the issue and the definition of a new model, termed the ARTS model which could explain most of the physical constraints that were inherently associated with the SDD model. In the ARTS model, gradient formation is mediated by the mRNA which is redistributed along cortical microtubules to form a mRNA gradient which is translated to form the protein gradient. Contrary to the SDD model, there is no Bcd diffusion from the tip. The ARTS model is also compatible with the observed cortical movement of Bcd. I will critically compare the SDD and the ARTS models as well as other models, analyze the major differences, and highlight the path where Bcd is localized during early nuclear cycles.
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Affiliation(s)
- Stefan Baumgartner
- Department of Experimental Medical Sciences, Lund University, BMC D10, S-22184 Lund, Sweden
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46
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Cencic R, Pelletier J. A cautionary note on the use of cap analogue affinity resins. Anal Biochem 2018; 560:24-29. [PMID: 30193929 DOI: 10.1016/j.ab.2018.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 09/02/2018] [Accepted: 09/03/2018] [Indexed: 10/28/2022]
Abstract
All cellular cytoplasmic mRNAs are capped at their 5' ends with an m7GpppN group. Several proteins that mediate cap function have been identified by cap affinity purification, enabling their characterization in a number of biological processes. Among these, eukaryotic initiation factor (eIF) 4E is the best characterized and plays a critical role in regulating ribosome recruitment to mRNAs during translation initiation. Cap affinity chromatography is often used to identify eIF4E-interacting proteins, which could play critical roles in molding the eIF4E-interactome and impacting on eIF4E-directed translation. Here we address how improper implementation of this technology can lead to false conclusions and provide recommendations to ensure correct interpretation of data obtained by this approach.
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Affiliation(s)
- Regina Cencic
- Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada; Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec, H3G 1Y6, Canada; Department of Oncology, McGill University, Montreal, Quebec, H3G 1Y6, Canada.
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47
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Jafarnejad SM, Chapat C, Matta-Camacho E, Gelbart IA, Hesketh GG, Arguello M, Garzia A, Kim SH, Attig J, Shapiro M, Morita M, Khoutorsky A, Alain T, Gkogkas CG, Stern-Ginossar N, Tuschl T, Gingras AC, Duchaine TF, Sonenberg N. Translational control of ERK signaling through miRNA/4EHP-directed silencing. eLife 2018; 7:e35034. [PMID: 29412140 PMCID: PMC5819943 DOI: 10.7554/elife.35034] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 02/01/2018] [Indexed: 02/06/2023] Open
Abstract
MicroRNAs (miRNAs) exert a broad influence over gene expression by directing effector activities that impinge on translation and stability of mRNAs. We recently discovered that the cap-binding protein 4EHP is a key component of the mammalian miRNA-Induced Silencing Complex (miRISC), which mediates gene silencing. However, little is known about the mRNA repertoire that is controlled by the 4EHP/miRNA mechanism or its biological importance. Here, using ribosome profiling, we identify a subset of mRNAs that are translationally controlled by 4EHP. We show that the Dusp6 mRNA, which encodes an ERK1/2 phosphatase, is translationally repressed by 4EHP and a specific miRNA, miR-145. This promotes ERK1/2 phosphorylation, resulting in augmented cell growth and reduced apoptosis. Our findings thus empirically define the integral role of translational repression in miRNA-induced gene silencing and reveal a critical function for this process in the control of the ERK signaling cascade in mammalian cells.
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Affiliation(s)
- Seyed Mehdi Jafarnejad
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
| | - Clément Chapat
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
| | - Edna Matta-Camacho
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
| | - Idit Anna Gelbart
- The Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
| | - Geoffrey G Hesketh
- Centre for Systems BiologyLunenfeld-Tanenbaum Research Institute, Sinai Health SystemTorontoCanada
| | - Meztli Arguello
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
| | - Aitor Garzia
- Laboratory for RNA Molecular BiologyHoward Hughes Medical Institute, The Rockefeller UniversityNew YorkUnited States
| | - Sung-Hoon Kim
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
| | - Jan Attig
- The Francis Crick InstituteLondonUnited Kingdom
| | - Maayan Shapiro
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
| | - Masahiro Morita
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
| | - Arkady Khoutorsky
- Department of AnesthesiaMcGill UniversityMontréalCanada
- Alan Edwards Centre for Research on PainMcGill UniversityMontréalCanada
| | - Tommy Alain
- Children’s Hospital of Eastern Ontario Research Institute, Department of Biochemistry, Microbiology and ImmunologyUniversity of OttawaOttawaCanada
| | - Christos, G Gkogkas
- Patrick Wild Centre, Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Noam Stern-Ginossar
- The Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
| | - Thomas Tuschl
- Laboratory for RNA Molecular BiologyHoward Hughes Medical Institute, The Rockefeller UniversityNew YorkUnited States
| | - Anne-Claude Gingras
- Centre for Systems BiologyLunenfeld-Tanenbaum Research Institute, Sinai Health SystemTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
| | - Thomas F Duchaine
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
| | - Nahum Sonenberg
- Goodman Cancer Research CenterMcGill UniversityMontréalCanada
- Department of BiochemistryMcGill UniversityMontréalCanada
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48
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Yamashita A, Takeuchi O. Translational control of mRNAs by 3'-Untranslated region binding proteins. BMB Rep 2018; 50:194-200. [PMID: 28287067 PMCID: PMC5437963 DOI: 10.5483/bmbrep.2017.50.4.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Indexed: 12/31/2022] Open
Abstract
Eukaryotic gene expression is precisely regulated at all points between transcription and translation. In this review, we focus on translational control mediated by the 3′-untranslated regions (UTRs) of mRNAs. mRNA 3′-UTRs contain cis-acting elements that function in the regulation of protein translation or mRNA decay. Each RNA binding protein that binds to these cis-acting elements regulates mRNA translation via various mechanisms targeting the mRNA cap structure, the eukaryotic initiation factor 4E (eIF4E)-eIF4G complex, ribosomes, and the poly (A) tail. We also discuss translation-mediated regulation of mRNA fate.
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Affiliation(s)
- Akio Yamashita
- Department of Molecular Biology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
| | - Osamu Takeuchi
- Laboratory of Infection and Prevention, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
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49
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Jia H, Sun W, Li M, Zhang Z. Integrated Analysis of Protein Abundance, Transcript Level, and Tissue Diversity To Reveal Developmental Regulation of Maize. J Proteome Res 2018; 17:822-833. [DOI: 10.1021/acs.jproteome.7b00586] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Haitao Jia
- National Key Laboratory of
Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Wei Sun
- National Key Laboratory of
Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Manfei Li
- National Key Laboratory of
Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Zuxin Zhang
- National Key Laboratory of
Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, P. R. China
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50
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Reichardt I, Bonnay F, Steinmann V, Loedige I, Burkard TR, Meister G, Knoblich JA. The tumor suppressor Brat controls neuronal stem cell lineages by inhibiting Deadpan and Zelda. EMBO Rep 2017; 19:102-117. [PMID: 29191977 DOI: 10.15252/embr.201744188] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 10/31/2017] [Accepted: 11/10/2017] [Indexed: 11/09/2022] Open
Abstract
The TRIM-NHL protein Brain tumor (Brat) acts as a tumor suppressor in the Drosophila brain, but how it suppresses tumor formation is not completely understood. Here, we combine temperature-controlled brat RNAi with transcriptome analysis to identify the immediate Brat targets in Drosophila neuroblasts. Besides the known target Deadpan (Dpn), our experiments identify the transcription factor Zelda (Zld) as a critical target of Brat. Our data show that Zld is expressed in neuroblasts and required to allow re-expression of Dpn in transit-amplifying intermediate neural progenitors. Upon neuroblast division, Brat is enriched in one daughter cell where its NHL domain directly binds to specific motifs in the 3'UTR of dpn and zld mRNA to mediate their degradation. In brat mutants, both Dpn and Zld continue to be expressed, but inhibition of either transcription factor prevents tumorigenesis. Our genetic and biochemical data indicate that Dpn inhibition requires higher Brat levels than Zld inhibition and suggest a model where stepwise post-transcriptional inhibition of distinct factors ensures sequential generation of fates in a stem cell lineage.
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Affiliation(s)
- Ilka Reichardt
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - François Bonnay
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Victoria Steinmann
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Inga Loedige
- Laboratory for RNA Biology, Biochemistry Center Regensburg (BZR), University of Regensburg, Regensburg, Germany
| | - Thomas R Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Gunter Meister
- Laboratory for RNA Biology, Biochemistry Center Regensburg (BZR), University of Regensburg, Regensburg, Germany
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
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